Refrigeration



Aug 18, 19317- J. G. BERGDOLL 1,819,861

REFRIGERATION n Filed Dec. 20. 195o Patented Aug. 18, 1931 u UNITEDSTATES- PATENT OFFICE JOHN G. BERGDOLL, 'OF YORK, PENNSYLVANIA, ASSIGNORT0 YORK ICE MACHINERY CORPORATION, 0F YORK, PENNSYLVANIA, A CORPORATION0F DELAWARE REFRIGERATION Application led December 20, 1930. Serial No.503,847.

This' invention relates to refrigeration, and

particularly to means for controlling the feedI of liquid refrigerant toflooded evaporators.

In my allowed 'application Serial No. 408,- 363, filedrNovember 19,1929, I describe and claim an arrangement of float control valve forfeeding liquid refrigerant to a flooded evaporator in which the floatvalve is located at a level above the liquid level in the evaporator.

`Generally stated, the float responds to the riseand fall of a column'of liquid, preferably refrigerant, which balances a liquid column in theevaporator, the'two columns reactlng against each other through apressure transmitting link of refrigerant vapor.

In the structure of the prior application, no means was providedforvvarying the liquid level maintain-ed in the evaporator, and theyobject of the present invention is to provide such means.

The present invention contemplates the adjustment of the vertical heightof the pressure transmitting link of refrigerant vapor. This may be donein various ways, for exam# ple, the vertical height of the upper end ofthe link may be varied, in which case the height of both liquid columnswillvary to correspond.

lAccording to another embodiment of the invention the vertical height ofthev lower end of the vapor column is varied, -in which case the heightof both liquid columns remains the same, but the datum plane for theliquid column :in the evaporator varies as the lower end of the vaporcolumn varies in height.

Two embodiments of the invention, one embodying each of the general@operative principles above outlined, are illustrated in theaccompanying drawings, inI which,-

Fig. 1 isa vertical elevation of a portion .Y of an evaporator includinga suction trap with the invention applied in that form in whichthevertical height of the upper end of the vapor column is adjustable. Inthis view, portions are sectioned to show 'the internal construction,and the parts are shown -in the position for maintaining the lowestavailable liquid level in the trap.

Fig. is a section on line 2-2 of Fig. 1.

In this view there is shown in full lines the adjustment for the lowestavailable liquid level, and lindotted lines an adjustment for .ahigherlevel.

a. modified form-in which the level of the lower end of the vapor columnis adjustable..

suction trap. The lower or liquid headers of the evaporator areindicated atl 7 and the upper or gas headers at 8. These are horizontaland are connected by riser tubes 9, of

` any suitable form,for example, the V-shaped riser` tubescharacteristic of the patent above 'identied The form, or even thepresence of the riser tubes, is not, however, material to the invention.l

The minimum liquid operating level in and another higher liquid levelwhich may le aintained is indicated by the line Connected to theupperend of the drum 6 is a suction line 11 which leads t0 the suction of thecompressor, not shown. 'The liquid 'supply line 12 is connected todeliver liquid refrigerant to the drum 6 either through a float controlvalve (normal operation) or through an expansion valve, but beforedescribing the connections, the construction and arrangement of theyfloat control valve will be explained.

The float valve mechanism includes a float chamber housing 13. From thetop of this there leads a pressure equalizing connection 14 to theinterior of the drum 6 above the highest liquid level to be maintainedtherein.

open stop valve 15. From the bottom' of the Itheevaporator is indicatedby the line A-A i' float chamber housing 13 a pipe 16 leads to thelowest liquid level to be. maintained in tlie interior of the drum 6, ata point below i ss Flg. 3 1s a vlew similar toFlg. 1, showingthe drum. Aliquid sealed trap is interposed between the pipe 16 and the drum 6,and, vin the embodiment of the invention here illustrated, this takesthe form o f an inverted U, 17, having at its ends alined mpples 18 and19, one of which swivels in the gland 21 at the lower end of the pipe16, and the otherof which swivels in a similar gland 22 connecteddirectly to the interior of the drum below the lowest liquid level to bemaintained therein. A brace is shown at 20.

' The right hand leg of the inverted U-trap 17 is li uid filled, and theleft hand leg is lled with refrigerant gas or vapor, as is clearlyindicated in- Fig. 1. The verticalA height defined by this tra isindicated by the line C--C and may be a justed 'to vary the verticalheight of the vapor column by tilting the member 17 from the verticalposition indicated in full lines in Fig. 2 to an iiiclined position, oneof which'is indicated in dotted lnes in that ligure. q

The presence of vapor in the left hand leg of the trap 17 is assured bythe .fact that the vapor evolvedfrom any liquid mthis leg is trappedagainst escape, and, consequently, displaces the liquid downward andinto the drum 6, until the left hand leg of the trap 17 is free ofliquid. f 0

The liquid level maintained in the trap chamber 13 is indicated by theline D-D.

When thel liquid rises in the chamber 13 to' the level D-D, the floatvalve stops the feedI and prevents thelevel from rising: higher.

A. normally open stop valve 23 controls low lthrough the pipe 16.

In theposit-ion illustratedin Fig. 1, and in thefu'll line position ofFig. 2, the liquid column H balances the liquid column H2,

the pressure between the columns being transmitted through thevapor. Thevapor co1- umn Serves as a substantially weightless fessure-transmittingm'edium interposed etween the two columns H', H2. n

If itis desired to raise the liquid level 1n the drum 6, the trap 17' isswung toan iiiclined position (one ofvwhich is indicated in dotted linesin Fig. 2). In the position shown in dotted lines, the liquid column H3,which is higher than the liquid column I-I, balances an equalliquidcolumn H4, which,

' consequently, is higher than the liquid column H2. Thus.the angularadjustment' of the trap member 17 permits adjustment of the liquid levelin the drum 6. I

While the fioat valve mechamsm might assume various forms and bevariously connected, the following construction and arrangement ispreferred:4

Within the ioat chamber 13 is a. float 24 carried by a. rod 25 which ispivoted at 26.v

The rod 25 has an offset arm 27 which is connected to rcciprocate'abalanced piston .slide valve 28. This valve is conventionallyillustrated as provided with a port 'groove 29,

which, in the lower position of the ioat,con-

nects an inlet port 31 with an outlet port 32. Leading from the outletvport 32 is a bleed port 33, which, when they valve 29 is in its openposition, delivers a small flow of liquid refrigerant to the interior ofthe chamber 13. When the liquid in the chamber 13 falls below the levelD-D, descent of the float 24 shifts the valve 28 to the left so that theport 29 connects the ports 31 and 32. At the level D-.D the valve 28laps the port 32 and-stops the flow. i

Liquid refrigerant arriving by the high pressure liquid line 12' passesthrough a normally open stop valve 34 to a strainer 35 and thence bypipe 36 to the port 31. When the Valve* 28 is open,all the liquid exceptthe small part which passes through the port 33 to the chamber 13,-lowsthrough the pipe 37 and normally open stop valve 38 tothe pipe 39,andthence to the interior of the drum 6. A normally closed by-pass valvev41 which may be used as an expansion valve is provided, so` that if itis desired to suspend the flow, the controlling valves 34 and 38 may beclosed and the valve'4l may be o ened, in which case liquid'refrigerantwill fed to the drum directly.

The port 3 3 has an important function. Since the space within thechamber 13 is connected with the vapor space in the drum 6 by theequalizing connection 14, some refrigi erant will evaporate in thechamber 13. 4The port 33 is designed to, feed refrigerant to the'lchamber 13 at a rate slightly in excess of the maximum loss ofrefrigerant from the chainber by evaporation." The excess, which .isslight, Hows down the pipe 16, up the right hand leg 'of the trap 17,and then passes `through the gasfilled leg of the trap 17 to the lowerend of the dru'm 6.-

frigerant so fed passes oli' as vapor through .the connection 14. Theslight excess whichl is provided is not sufficient to flood the gasflled leg of the member 17 'and thus -exerts no disturbing effect. v

The construction of the float valve has been illustrated in a simple andsomewhat diagrammatic form, and maybe departed from in practice., Forexample, I contemplate the use ofthe float valve illustrated in` detailin my allowed application, above referred to,- but as the function ofthat valve' is in no way different from the function of `thevalve justdescribed, it is unnecessary to vThe supply ofliquid to the chamber `13is.- ery limited, so limited that most of the rethe lower end of the gasfilled pipe. One

the feature that the vertical hei-ght of the gas such structure isillustrated in Fig. 3, and in this particular embodiment, the effectivelength of the gas filled pipe, only, is'varied,

5 the height of the two balanced liquid columns remaining constant.However, this varies the datum plane, from which the column in theevaporator is measured, with the result that the actual level in theevaporator drum is changed.

InFig. 3 the construction and arrangement of many parts are unchanged,and accordingly they bear the same reference numerals as identicalpartsin Figs. 1 and 2. Such identical parts are those numbered 6 to 16inclusive, 23, and 34 to 41 inclusive. In- Fig. 3 the internalconstructionof the float valve mechanism, indicated generally by thenumeral 13, is not shown, but it is to 20 be understood that it conformsto the showing in Fig. 1 and contains the parts 24 to 33 inclusive. l

The pipe 16 instead of leading to a swinging inverted trap 17, isformed`with a trap loop 42, which leads by an offset 43 intotherelatively large vertical pipe 44 which communicates at its lower endwith the drum 6, at.a level lower than the lowest level to be maintainedin the drum. The upper end of the pipe 44, above the offset 43, isprovided with a packing gland 45, through which is slidably adjustable.in a vertical direction, a dip pipe 46. The upper end of the dip pipe 46is connected by a flexible tube 47 with the interior of `the drum 6above the highest liquid level to be maintained therein. A convenientway of making the connection is to connect the flexible pipe 47 directlywith the pressure equalizing pipe 14, as shown in Fi 3.

rgn annular space is afforded between the outside of the di-p pipe 46and the inner side of the vertical pipe 44. Consequently, refrigerantvapor evolved in the pipe 44 is trapped and displaces liquid refrigerantin the pipe. 44 down to the level of the lower end of the dip pipe 46.It follows, therefore, that the effective liquid column in the trap 13,which is represented atl-I5, is balanced by the eective liquid column H6in the drum 6.

The datum line E-E is determinedby the lower end of the dippipe 46,foras soon as the gas displaces the liquid downward in the pipe 44 tothis datum line, the ldisplacement will be arrested b the escape ofthegas upwardly through t e dip pipe 46. In thls arrangement the column ,H51s constant, and bein equal to the column H6 they latter must also e aconstant, but sincethe column H is measured from the datum plane E-E andsince the datum plane may be adjusted vertically by adjusting the dippipe 46 vertically, itis possible to establish different levels in thedrum 6 by moving the dip pipe 46 up i and down.

Both these arrangements have in common or vapor leg which serves asapressure transmitting link between the two liquid columns, isadjustable.

Various other arrangements within the scope of the. invention arepossible,`and are contemplated. The gist of the invention is the use ofa float control valve located at al fixed level, and preferably at alevel above the liquid level to be maintained in the evaporator, tomaintain various desired levels in thev evaporator, the. result beingsecured by cont-rol of the gas filled link which serves as a pressuretransmitting medium betweenathe two liquid columns, i. e., thatcontrolled by the float, and that existing in the evaporator.

In certain of the claims the portion of pipe 16 above the. seal affordedby the inverted U-trap 17 (Figs. 1 and 2), or above the seal 'aorded bythe loop 42 (Fig. 3), together with the liquid-filled portion of chamber13,

are referred to as a liquid-containing manometer fo-r in effect suchliquid column functions as a manometer. I

What is claimed is,-

1. The combination with an evaporator, of

means for maintaining a desired liquid levely therein, comprising aliquid containing manorneter;v a valve controlling the supply of liquidrefrigerant to the evaporator; operating means for said valve responsiveto the height of the liquid in said manometer; a pressure transmittingconnection between said manometer and a point within the evaporatorbelow the liquid level therein; means for developing in said connectiona vapor pressure at least equal to the head of the liquid refrigerant at.said point; and means for varying the vertical height of the vaporfilled portion of said pressure transmitting connection.

2. 'The combination with an evaporator, of means for maintaining adesired liquid level therein, comprising a liquid containing manometer;a valve controlling the'supply of liquid refrigerant to the evaporator;operating means foi` said valve responsive to the height of the liquidin saidmanometer; a

pressure equalizing connection between the upper end of the manometerandthe vapor space above the liquid in the evaporator;l a

'pressure transmitting connection between saidvmanometer and a'pointwithin the evap orator below the liquid level therein; means fordeveloping in said connection a vapor pressure at least equal to thehead ofthe liquid refrigerant at said point; and means for varying thevertical height of the vaporfilled portion of said pressure transmittingconnection. j

3. The combinationwith an evaporator, `of meansau for maintaining adesired liquid level therein, comprising wa manomer con- `taining acolumn of liquid refrigerant; a

valve controlling the supply of liquid refrigerant to the evaporator;operating means for said valve responsive to the height of the liquidcolumn in said manometer; a pressure transmitting connection betweensaid manometer and a point within the evaporated below the liquid levelvtherein; means for developing in said connection 'a refrigerant vaporpressure at least equal to the head of the liquid refrigerant at saidpoint; and means for varying the vertical height of the vapor filledportion of said pressure transmitting connection.

4. The combination with an evaporator, of means for maintaining adesired liquid level therein, comprising a manometer containing a columnof liquid refrigerant, a valve controlling the supply of liquidrefrigerant to the evaporator; operating means for said valve responsiveto the height of the liquid column in said manometer; a pressureequalizing connection between the upper end of the manometer and thevapor space above the liquid in the evaporator; a pressure transmittingconnection between said manometer and a point within the evaporatorbelow the liquid level therein; means for developing in said connectiona refrigerant vapor pressure at least equal to the head of the liquidrefrigerant at said point; and means for varying the vertical height ofthe vapor filled portion of said pressure transmitting connection.

5. The combination with an evaporator, of means for maintaining adesired constant .liquid level therein, comprising a manometercontaining a column of liquid refrigerant; a valve controlling thesupply of liquid refrigerant to the evaporator; operating means for saidvalve responsive to the height of the liquid column in said manometer; apressure equalizing connection between the upper end of the manometerand the vapor space above the liquid in the evaporator; a pressuretransmitting connection between said manometer and a point within theevaporator below thev liquid level therein; means fon developing insaidconnection a refrigerant vapor pressure at least equal to the head ofthe liquid refrigerant at said point; means for varying the verticalheight vof the vapor filled portion of said pressure transmittingconnection and means for supplying liquid refrigerant to said manometercolumn at a restricted rate.

6. The combination with an evaporator, of means for maintaining adesired constant liquid level therein, comprising a valve controllingthe supply of liquid refrigerant to the evaporator; a fioat chamber anda liquid sealed trap arranged to define a manometer column; a pressureequalizing connection from the float chamber to the vapor space of theevaporator; a pressure transmitting vapor filled connection between thetrap the evaporator; a float chamber and a liquid.

sealed trap arranged to define a manometer column; means for adjustingthe vertical height of said trap, whereby the height of the manometercolumn is varied; a pressure equalizing connection from the floatchamber to the vapor spaceof the evaporator; a pressure transmittingconnection between the trap and a point within the evaporator below theliquid level therein; and a float in said float chamber connected toclose said valve upon 'a riseof liquid level in said chamber. l

8. The combination with an evaporator, of means for maintaining asubstantially constant liquid level therein comprising a valvecontrolling the supply of liquid refrigerant to the evaporator; a floatchamber andra liquid sealed trap arranged to define a manometer column:a pressure equalizing connection from the float chamber to the vaporspace of the evaporator; a pressure transmitting vapor filled connectionbetween 'the trap and a point within the evaporator bclow the liquidlevel therein; means for variably, defining the lower end of said vaporfilled connection; and a iioat in said fioat chamber connected to closesaid valve upon a rise of liquid level in said chamber.

9. The 'combination with an evaporator. of means for maintaining adesired liquid level therein comprising a valve controlling the supplyofliquid refrigerant to the evaporator; a fioat chamber and a liquidsealed trap arranged to define a manometer column; means for adjustingthe vertical height of said tra-p; a pressure-equalizing connection fromthe float chamberpto the vaporspace of the evaporator; a pressuretransmitting connection between the trap and a point withintheievaporator below the liquid level therein-fa` fioat in said floatchamber connected to close said valve upon a rise of liquid level insaid chamber; and means for feeding liquid refrigerant .at a restrictedrate to said chamber.

1,0. The combina-tion with'an evaporator, of means for maintaining adesired liquid level therein comprising a' valve controlling the supplyof liquid refrigerant to the evaporator; a float chamber and a liquidsealed trap arranged to define a manometer column; a pressuree'qualizing connection from the float chamber to the vapor space ofthe-evaporator; a vapor filled pressure transmitting connectionbetweenthe trapand a point within the evaporator below the liquid leveltherein; means for varying the vertical height of said vapor filledconnection; a float in said float chamber connected to close'said valveupon a rise of liquid level in said chamber; and means for feedingliquid refrigerant at a restricted rate to said chamber.

11. The combination with an evaporator, of means for maintaining adesired liquid level therein comprising a valve controlling the supplyof liquid refrigerant to the evaporator; a float chamber and a liquidsealed trap arranged to define a manometer column; a pressure equalizingconnection from the float chamber to the vapor space of the evaporator;a vapor filled pressure transmitting connection between the trap and apoint within the evaporator below the liquid level therein; means foradjusting vertically', the lower end of said vapor filled connection; afloat in said float chamberl connected to close saidvalve upon a rise ofliquid level in said chamber; and means for feeding liquid refrigerantat a restricted rate to said chamber.

12.- The combination with an evaporator,`

. mitting-connection and the lower end of the manometer column; meansfor adjusting the trap to vary the height of the lowerend of themanometer column; and means responsive to the height of the upper end ofthe manometer column for opening and closing said valve as said upperend falls and rises.

13. The combination with an evaporator, of means for maintaining adesired liquid level therein, comprising a valve controlling the supplyof liquid refrigerant tothe evaporator; a manometer column; a pressureequalizing connection from the top of the manometer column to the vaporspace of the evaporator; a partially vapor-filled pressure transmittingconnection between the lower end of the manometer column and a point inthe evaporator below the desired liquid level therein; a trap interposedbetween the pressure transmitting connection and thelower end of themanometer column; an adjustable vent leading from the lower portion ofthe pressure transmitting connection to the vapor space in theevaporator and serving when adjusted to determine at will the lower endof the vapor filled portion thereof; and means responsive to the heightof the upper end of the manometer column for opening and closng saidvalve as said upper end rises and alls.

14. The combination with an evaporator, of means for maintaining adesired liquid level therein, comprising a 'fixed manometer containing acolumn of liquid refrigerant; a valve controlling the supply of liquidrefrigerant to the evaporator; operating means for said valve responsiveto the height of the liquid column in said manometer; a pressuretransmitting connection between said manometer and a point within theevaporator below the liquid level therein; means for developing in saidconnection a refrigerant vapor pressure at least equal to the head ofthe. liquid refrigerant at said point; and means associated with saidpressure transmitting connection for varying the relation between theliquid column in the manometer and the height .of liquid in theevaporator.

15. The combination with an evaporator, of means for maintaining adesired liquid level therein, comprising a fixed manometer containing acolumn of liquid refrigerant; `a valve controlling the supply of liquidrefrigerant to the evaporator; operating means for said valve responsiveto the helght of the liquid column in said manometer; a pressureequalizing connection between the upper end of the manometer and thevapor space above the liquid in the evaporator; a pressure transmittingconnection between said manometerv and a point within theevaporatorbelow the liquid level therein; means for developingin said connection arefrigerant vapor pressure at least equal to the head of theliquidrefrigerant at said point; and means associated with said pressuretransmitting connection for varying the relation between the liquidcolumn in thevmanometer and the height of li uid in the evaporator ntestimony whereof I have signed my name to this specification.

JOHN G. BERGDOLL.

